A method for writing and reading data in a hard disk drive and compensating for an offset between a write element and a read element of a head. The method determines an offset time by determining the difference between a desired sync byte position and an actual sync byte position located between a preamble and a data sector of the disk. The difference corresponds to the offset between the read and write elements. The offset time is subtracted from the normal time for enabling the read gate of a disk drive pre-amplifier.
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13. A hard disk drive, comprising:
a disk; a spindle motor coupled to said disk; a head coupled to said disk, said head having a read element that is separated from a write element by an offset; and, circuit means for enabling said read element as a function of the offset.
25. A method for enabling a read gate of a hard disk drive, comprising:
reading a sync address mark of a disk with a head that has a read element offset from a write element; generating a sector signal; and, enabling a read gate signal at a time that is a function of the offset.
1. A hard disk drive, comprising:
a disk; a spindle motor coupled to said disk; a head coupled to said disk, said head having a read element that is separated from a write element by an offset; and, an electrical circuit that enables said read element as a function of the offset.
26. A method to determine an offset between a read element and a write element of a hard disk drive, comprising:
determining a desired sync byte location on a disk; reading a disk with a head that has a read element; determining an actual sync byte location of the disk; and, generating offset information as a difference between the desired and actual sync byte locations.
39. A method for controlling the operation of a data storage device that has a read element physically offset from a write element, comprising:
generating a write signal that is subsequent in time to a first periodic timing reference signal to initiate a write operation through the write element; and, generating a read gate signal that precedes in time a second periodic timing reference signal to initiate a read operation through the read element.
41. A circuit that controls a read/write operation of a data storage device that has a read element and a write element that are physically offset from each other, comprising:
a controller that generates a periodic timing reference signal, and a read gate signal that indicates a start of a read operation, said read gate signal being offset in time from the periodic timing reference signal by a duration that corresponds to the physical offset between the read element and the write element.
43. A method for controlling the read/write operation of a data storage device that has a read element and a write element that are physically offset from each other, comprising:
generating a write signal that is subsequent in time to a first periodic timing reference signal by an offset duration to initiate a write operation through the write element; and, generating a read gate signal that precedes in time a second periodic timing reference signal to initiate a read operation through the read element.
32. A circuit that controls a read/write operation of a data storage device that has a read element and a write element that are physically offset from each other, comprising:
a controller that generates a periodic timing reference signal, a read gate signal that precedes in time said periodic timing reference signal and indicates a start of a read operation, and a write gate signal that is subsequent in time to said periodic timing reference signal by an offset duration and indicates a start of a write operation.
36. A data storage device, comprising:
a storage medium; a head coupled to said storage medium, said head having a read element that is physically offset from a write element; a controller that generates a periodic timing reference signal, a read gate signal that precedes in time said periodic timing reference signal and indicates a start of a read operation, and a write gate signal that is subsequent in time to said periodic timing reference signal by an offset duration and indicates a start of a write operation.
45. A method of compensating for a physical offset between a read element and a write element of a data storage device, comprising:
writing a data pattern onto a storage medium, the data pattern including a preamble portion that has a start point; determining a time duration between the start point of the preamble and a periodic timing reference signal; and, offsetting at least one of a read gate signal and a write gate signal from said periodic timing reference signal by said determined time duration, said read gate signal indicating a start of a read operation, said write gate signal indicating a start of a write operation.
20. A hard disk drive, comprising:
a disk that has a sync address mark, a data sector, a preamble to said data sector, and a sync byte located between said preamble and said data sector; a spindle motor coupled to said disk; a head coupled to said disk, said head having a read element that is separated from a write element by an offset; a pre-amplifier circuit connected to said head, said pre-amplifier circuit having a read gate coupled to said read element; a read/write channel circuit connected to said pre-amplifier circuit; and, controller means for providing a read gate signal to said read gate to enable said read element, a timing of said read gate signal being a function of the offset.
8. A hard disk drive, comprising:
a disk that has a sync address mark, a data sector, a preamble to said data sector, and a sync byte located between said preamble and said data sector; a spindle motor coupled to said disk; a head coupled to said disk, said head having a read element that is separated from a write element by an offset; a pre-amplifier circuit connected to said head, said pre-amplifier circuit having a read gate coupled to said read element; a read/write channel circuit connected to said pre-amplifier circuit; and, a controller connected to read/write channel circuit and said pre-amplifier circuit, said controller provides a read gate signal to said read gate to enable said read element, a timing of said read gate signal being a function of the offset.
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This application is based on U.S. Provisional Application No. 60/279,136, filed on Mar. 26, 2001.
1. Field of the Invention
The present invention relates to reading data in a disk drive and compensating for an offset between a read element and a write element of a head.
2. Background Information
Hard disk drives contain a plurality of magnetic heads that are coupled to rotating disks. The heads write and read information by magnetizing and sensing the magnetic fields of the disk surfaces. There have been developed magnetic heads that have a write element for magnetizing the disks and a separate read element for sensing the magnetic fields of the disks. The read element is typically constructed from a magneto-resistive material. The magneto-resistive material has a resistance that varies with the magnetic fields of the disk. Heads with magneto-resistive read elements are commonly referred to as magneto-resistive (MR) heads.
Each head is attached to a flexure arm to create a subassembly commonly referred to as a head gimbal assembly ("HGA"). The HGA's are suspended from an actuator arm. The actuator arm has a voice coil motor that can move the heads across the surfaces of the disks.
Information is typically stored in radial tracks that extend across the surface of each disk. Each track is typically divided up into a number of segments. The voice coil motor and actuator arm can move the heads to different tracks of the disks.
The head is typically connected to a pre-amplifier circuit that has a read gate and a separate write gate. Enabling the write gate allows information to be written onto the disk through the write element of the head. Enabling the read gate allows information to be read from the disk through the read element.
As shown in
The write element is typically offset from the read element of an MR head. Consequently, some of the preamble is actually written prematurely so that the read element misses a portion of the preamble during a read routine. The preamble is used to phase lock the circuits of the disk drive to allow for proper reading of the data in the subsequent DATA sector(s). Without a sufficient amount of preamble to read, the disk drive may not acquire proper phase lock. A lack of phase lock may cause errors in reading the data. This problem can be alleviated by increasing the length of the preamble so that there is enough preamble data to allow phase lock. Unfortunately, stretching the preamble reduces the storage capacity of the disk drive.
A hard disk drive that includes a head coupled to a disk. The head includes a read element offset from a write element. The drive further includes electrical circuits that enable the read element as a function of the offset.
Disclosed is a method for writing and reading data in a hard disk drive and compensating for an offset between a write element and a read element of a head. The method determines an offset time by determining the difference between a desired sync byte position and an actual sync byte position located between a preamble and a data sector of the disk. The difference corresponds to the offset between the read and write elements. The offset time is subtracted from the normal time for enabling the read gate of a disk drive pre-amplifier.
Referring to the drawings more particularly by reference numbers,
The disk drive 10 may include a plurality of heads 20 located adjacent to the disks 12. As shown in
Referring to
The hard disk drive 10 may include a printed circuit board assembly 38 that includes a plurality of integrated circuits 40 coupled to a printed circuit board 42. The printed circuit board 40 is coupled to the voice coil 32, heads 20 and spindle motor 14 by wires (not shown).
The read/write channel circuit 62 is connected to a controller 64 through read and write channels 66 and 68, respectively, and read and write gates 70 and 72, respectively. The read gate 70 is enabled when data is to be read from the disks 12. The write gate 72 is to be enabled when writing data to the disks 12. The controller 64 may be a digital signal processor that operates in accordance with a software routine, including a routine(s) to write and read data from the disks 12. The read/write channel circuit 62 and controller 64 may also be connected to a motor control circuit 74 which controls the voice coil motor 36 and spindle motor 14 of the disk drive 10.
The write gate WG can be enabled at the trailing edge of the SECTOR signal wherein preamble data, the sync byte SB and data are written onto the disk. Because the write element is offset from the read element, a portion of the PREAMBLE is actually written prematurely. The PREAMBLE allows the read/write channel to phase lock onto the data in the DATA sector.
To insure that all of the preamble data is properly read and the read/write channel acquires phase lock, the read gate is enabled a predetermined time interval before the SECTOR signal. This time interval will be referred to as the offset time t1. The time at which the read gate is enabled is determined by subtracting the offset time from a normal or non-offset time shown in phantom in FIG. 4. The early enablement of the read gate allows all of the PREAMBLE to be read and allow phase lock and subsequent reading of data in the data sector.
The offset time t1 used to shift the read gate RG during operation is computed in block 158 based on the timing differential t2-t3. In block 160, the offset time is stored in memory, typically on the disk(s). In decision block 162 the head 20 is moved to an adjacent track where steps 150-160 are repeated, unless the head 20 is at the last track. In decision block 162, steps 150-162 are repeated for a different head unless all of the heads have been processed.
The offset times for each head and each track can be stored in memory and then retrieved by the controller to shift the enablement of the read gate RG to insure that the entire PREAMBLE is read and the read/write channel acquires phase lock for subsequent data retrieval.
While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention not be limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those ordinarily skilled in the art.
For example, although the offset was determined by measuring the time interval between the sync byte and SECTOR signal, the actual and desired position of the sync byte may be referenced from the SAM signal.
Chu, Sang Hoon, Lee, Kang Seok, Yun, Jong Yun, Kim, Gyu Tack
Patent | Priority | Assignee | Title |
7006316, | Aug 16 2004 | Western Digital Technologies, Inc. | Estimating a writer/reader gap in a disk drive by measuring write/read times relative to a sync mark |
7106534, | Mar 26 2003 | Western Digital Technologies, INC | Method for compensating timing to start data recording and magnetic disk device using same |
7388817, | Jul 04 2003 | Kabushiki Kaisha Toshiba | Method and apparatus for measuring head gap length of composite head |
7499237, | Jul 19 2005 | Samsung Electronics Co., Ltd. | Recording controlling method in hard disk drive and hard disk drive using the same |
8749911, | Mar 11 2013 | Western Digital Technologies, INC | Disk drive accounting for fractional clock cycle when measuring reader/writer gap |
9013818, | Dec 06 2013 | Western Digital Technologies, INC | Disk drive measuring reader/writer gap by measuring fractional clock cycle over disk radius |
Patent | Priority | Assignee | Title |
3834392, | |||
4343300, | Sep 20 1979 | Olympus Optical Co., Ltd. | Data transmission system for an endoscope apparatus |
4499895, | Oct 15 1981 | Olympus Optical Co., Ltd. | Endoscope system with an electric bending mechanism |
4572198, | Jun 18 1984 | Varian, Inc | Catheter for use with NMR imaging systems |
4573452, | Jul 12 1984 | Surgical holder for a laparoscope or the like | |
4601705, | Oct 31 1983 | BRIAN GLASGOW MEMORIAL FOUNDATION, THE, A CHARITABLE TRUST; CATHETER RESEARCH, INC , AN IN CORP | Steerable and aimable catheter |
4621618, | Feb 28 1984 | Olympus Optical Company, Ltd. | Dual viewing and control apparatus for endoscope |
4633304, | Aug 27 1983 | Olympus Optical Co., Ltd. | Endoscope assembly |
4672963, | Jun 07 1985 | Apparatus and method for computer controlled laser surgery | |
4758222, | Oct 31 1983 | BRIAN GLASGOW MEMORIAL FOUNDATION, THE, A CHARITABLE TRUST; CATHETER RESEARCH, INC , AN IN CORP | Steerable and aimable catheter |
4785806, | Jan 08 1987 | Yale University | Laser ablation process and apparatus |
4788975, | Nov 05 1987 | TRIMEDYNE, INC | Control system and method for improved laser angioplasty |
4790813, | Jan 03 1984 | INTRAVASCULAR SURGICAL INSTRUMENTS, INC , A CORP OF PA | Method and apparatus for surgically removing remote deposits |
4802033, | Nov 07 1986 | Eastman Kodak Company | Predictive positioning offset compensation for high TPI disk systems |
4875897, | Jun 12 1981 | Regents of University of California | Catheter assembly |
4887605, | Feb 18 1988 | Laser catheter delivery system for controlled atheroma ablation combining laser angioplasty and intra-arterial ultrasonic imagining | |
4974607, | Aug 20 1987 | TSURUTA, YOZO | System for centralized management of medical data |
4982295, | Jan 28 1988 | MITSUMI ELECTRIC CO , LTD , NO 8-2, 8-CHOME, KOKURYO-CHO, CHOFU-SHI, TOKYO, JAPAN, A CORP OF JAPAN | Method for centering a read/write head of a magnetic data storage apparatus on a track of a magnetic disk |
4996975, | Jun 01 1989 | Kabushiki Kaisha Toshiba | Electronic endoscope apparatus capable of warning lifetime of electronic scope |
5078714, | Mar 02 1990 | Method and apparatus for placement of a probe in the body and the medical procedure for guiding and locating a catheter or probe in the body | |
5104392, | Mar 22 1985 | Massachusetts Institute of Technology | Laser spectro-optic imaging for diagnosis and treatment of diseased tissue |
5125888, | Jan 10 1990 | University of Washington | Magnetic stereotactic system for treatment delivery |
5170299, | Aug 17 1990 | Maxtor Corporation | Edge servo for disk drive head positioner |
5203781, | Dec 19 1991 | AOB PROPERTIES LIMITED PARTNERSHIP | Lumbar arthroscopic laser sheath |
5217001, | Dec 09 1991 | Granit Medical Innovations LLC | Endoscope sheath and related method |
5217003, | Mar 18 1991 | Wilk Patent Development Corporation | Automated surgical system and apparatus |
5217453, | Mar 18 1991 | Automated surgical system and apparatus | |
5228429, | Jan 14 1991 | Position measuring device for endoscope | |
5233482, | Jul 31 1991 | HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B V ; MARIANA HDD B V | Thermal asperity compensation for PRML data detection |
5235478, | Dec 15 1989 | Sony Corporation | Disc drive apparatus with servo tracks offset from data tracks |
5259365, | Jul 26 1989 | United States Department of Energy | Endoscope examination apparatus |
5268803, | Jan 31 1991 | SONY CORPORATION A CORP OF JAPAN | Disc memory apparatus utilizing detection of high-accuracy address data in short servo sectors for high speed accessing |
5274510, | May 21 1990 | SONY CORPORATION A CORPORATION OF JAPAN | Track address pattern for a disk memory apparatus |
5301080, | Dec 31 1992 | HGST NETHERLANDS B V | Bias servo loop for magneto-resistive read/write head |
5335121, | Oct 01 1991 | U.S. Philips Corporation | Arrangement for reproducing a digital signal from a track on a magnetic record carrier using a read head with magneto-resistive element and an equalizer filter |
5335123, | Feb 21 1990 | MATSUSHITA ELECTRIC INDUSTRIAL CO , LTD , 1006, OAZA-KADOMA, KADOMA-SHI, OSAKA-FU, 571 JAPAN | Apparatus and method for head-positioning on a rotatable recording medium |
5367409, | Apr 29 1993 | International Business Machines Corporation | Even harmonic distortion compensation for digital data detection |
5368015, | Mar 18 1991 | Wilk Patent Development Corporation | Automated surgical system and apparatus |
5384671, | Dec 23 1993 | Maxtor Corporation | PRML sampled data channel synchronous servo detector |
5388127, | Feb 09 1993 | Hitachi America, Ltd. | Digital timing recovery circuit |
5402280, | May 11 1992 | Maxtor Corporation | Method and apparatus for runout correction due to disk slip or spindle imbalance |
5483393, | Apr 18 1994 | BANKBOSTON, N A , AS AGENT | Disk drive having head positioning servo with improved servo read signal processing using median servo burst peak magnitudes |
5497111, | Dec 22 1994 | International Business Machines Corporation | Peak detection circuit for suppressing magnetoresistive thermal asperity transients in a data channel |
5500776, | Dec 16 1993 | Seagate Technology LLC | Self-calibration for computer disk read/write offsets |
5523899, | Nov 22 1991 | RESEARCH INVESTMENT NETWORK, INC | Method and apparatus for thermal calibration of hard disk drive |
5539714, | Sep 25 1991 | MOBILE STORAGE TECHNOLOGY INC | Adaptive runout compensation for miniature disk drives |
5566101, | Aug 15 1995 | TEMPO SEMICONDUCTOR, INC | Method and apparatus for a finite impulse response filter processor |
5581420, | Mar 08 1993 | Western Digital Technologies, INC | Method and system for determining a radial positioning valve used for writing tracks at a desired track pitch |
5587850, | Aug 26 1994 | Maxtor Corporation | Data track pattern including embedded servo sectors for magneto-resistive read/inductive write head structure for a disk drive |
5590154, | Jun 26 1995 | Freescale Semiconductor, Inc | Equalizer circuit and a method for equalizing a continuous signal |
5606469, | Mar 30 1992 | Toshiba Storage Device Corporation | Method for correcting offset in a magnetic disk including apparent offtrack cancellation |
5608587, | Aug 06 1993 | Seagate Technology LLC | Method using magnetic disk servo pattern with buried identification patterns |
5615058, | Mar 08 1993 | Western Digital Technologies, INC | Method and system for writing a servo-pattern on a storage medium |
5715105, | Sep 28 1992 | Hitachi Global Storage Technologies Japan, Ltd | Method of and apparatus for recording on and reproducing from disk-type recording medium having recording tracks with sectors each having an ID area and a data area |
5781133, | Jan 30 1997 | Seagate Technology LLC | Method and apparatus for implementing run length limited codes |
5822143, | Jun 11 1996 | BANKBOSTON, N A , AS AGENT | Decision feedback equalization implementation of partial-response signaling in a magnetic recording channel |
5844920, | Nov 07 1996 | Cirrus Logic, INC | Thermal asperity compensation using multiple sync marks for retroactive and split segment data synchronization in a magnetic disk storage system |
5862007, | Apr 18 1996 | SAMSUNG ELECTRONICS CO , LTD | Method and apparatus for removing baseline shifts in a read signal using filters |
5898532, | Jul 02 1996 | Seagate Technology LLC | MR head thermal asperity recovery |
5905601, | May 16 1995 | Kabushiki Kaisha Toshiba | Apparatus for reproducing data having a restart read gate signal generator in a disk storage system |
5961658, | May 23 1997 | AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LIMITED | PR4 equalization and an EPR4 remod/demod sequence detector in a sampled amplitude read channel |
5986847, | Oct 18 1996 | SAMSUNG ELECTRONICS CO , LTD | Method and apparatus for providing read and write skew offset information for a magneto-resistive head |
6094316, | Mar 27 1998 | SAMSUNG ELECTRONICS CO , LTD | Method and apparatus for providing thermal asperity compensation in a fixed delay tree search detector |
EP79524, |
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